II. THE CHRONIC INFLAMMATORY DISEASES.
TUBERCULOSIS is one of the most dreadful and, un-
fortunately, most common diseases of mankind. It affects
alike the, young and the old, the rich and the poor, the
male and the female, the enlightened and the savage.
Nor do its ravages cease with human beings, for it is
common among animals, occurring with great frequency
among cattle, less frequently among goats and hogs, and
sometimes, though rarely, among sheep, horses, dogs,
Wild animals under natural conditions seem to escape
the disease, but when caged and kept in zoological gar-
dens even the most resistant of them—lions, tigers, etc.—
are said at times to succumb to it, while it is the most
common cause of death among captive monkeys.
The disease is not even limited to mammals, but occurs
in a somewhat modified form in birds, and, it is said,
even at times affects reptiles.
It is not a disease of modern times, but one which has
persisted through centuries; and though, before the ad-
vent of the microscope, not always clearly separated
from cancer, it has not only left unmistakable signs of
its existence in the early literature of medicine, but has
also imprinted itself upon the statute-books of some
countries, as Naples, where its ravages were great and
the means taken for its prevention radical.
While the great men of the early days of pathology
clearly saw that the time must come when the parasitic